1. Field of the Invention
The present invention relates to an electrodeless lighting system, and particularly, to an electrodeless lighting system capable of lateral lighting like a streetlight and configured to smoothly emit the internally generated heat to the outside.
2. Description of the Background Art
As a conventional lighting system used for lateral lighting like a streetlight, a high pressure mercury lamp, a high pressure sodium or a metal halide lamp of 400 W or 250 W are commonly used. A structure thereof is shown in FIG. 1.
As shown in FIG. 1, a conventional streetlight includes: a casing 3 composed of an upper case 1 and a lower case 2; an arm 4 for fixing the casing 3 to a pole (not shown); a reflector 5 installed in the upper case 1; a lamp 11 installed inside the reflector 5; a receptacle 6 for fixing the lamp 11; and a ballast 7 connected to the lamp 11 by a power line 12 to stably apply power to the lamp 11.
A transparent cover 8 is installed at the lower case 2 so that light coming out of the lamp 11 can be transmitted therethrough. Also, the lower case 2 is hingeably connected to the upper case 1, and may be coupled to or disjointed from the upper case 1 by a clamp 10 installed at a front end portion of the upper case 1.
However, the lamp 11 used for the conventional streetlight as above has problems that its life span is very short, which causes frequent replacement, and its lighting effect is very low.
Therefore, recently, many researchers are performing various researches related to technologies of employing an electrodeless lighting system using plasma having advantages of a long life span of a lamp and good lighting effect, and related prototypes are being made.
Such an electrodeless lighting system is a lighting device in which microwave energy generated from a magnetron, a power source, is transmitted to a resonator through a waveguide, and is applied to an electrodeless bulb installed in the resonator, and thus the bulb emits visible light or ultraviolet light. The electrodeless lighting system has a long life span and good lighting effect compared with incandescent lamps and fluorescent lamps that are generally used. However, the electrodeless lighting system used for lateral lighting such as a streetlight whose technology is open or which is released as products is great in size because it employs a forced air cooling method using a cooling fan to cool heat generated from components. For this reason, it is difficult to make its structure compact and simple.
In addition, the conventional electrodeless lighting system also has a problem that a noise is generated due the driving of the cooling fan and the air flow due to the driving thereof.